Genuine question - who builds linked lists from scratch today ? The only place I found where you had to build a linked list was in LRU cache.

Also who writes LRU cache from scratch as you have it already available in Redis ?

What exactly does the understanding of LinkedLists prove - I mean I love linked lists not because of their usefulness, because they are easy to reason about and learn in somewhat an adaptive way. Other than that I'm curious to know the actual usefulness of this skill as mostly you are using lists, deques etc.